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Research on a 50 kW digital inverter type plasma cutting power supply

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China Welding 2014年第2期23卷 51-56页

作者： Wang Zhenmin Fang xiaoxin zhang Xin Feng Yunliang School of Mechanical & Automotive Engineering South ChinaUniversity of Technology Guangzhou 510640

To improve energy transfer efficiency and quality controllability of plasma cutting process of thick plate, a 50 kW digital inverter type plasma cutting power supply is developed. The power supply main circuit is composed of two similar power electronic building blocks, using full-bridge high frequency inverter topology to achieve efficient energy transformation. To realize accurate digital control of the plasma cutting power supply and cooperative work of the two power electronic building blocks, the Cortex-M4 type ARM microprocessor-TM4C123GH6PGE is used as the cybernetic core of the control system. To improve the response performance and reliability of the power system, close-loop control and peak current feedback control modes are adopted. In the end, the experimental study of the performance testing and cutting of the developed prototype is carried out. The results indicate that the design is rational and feasible, and the developed high power plnsma cutting power supply works reliably with excellent performance.

关键词： plasma cutting digital control Cortex-M4 inverter

Synthesis and methane storage of binder-free porous graphene monoliths

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Particuology 2013年第4期11卷 415-420页

作者： Guoqing Ning Hao Wang xiaoxin zhang Chenggen Xu Guangjin Chen Jinsen Gao State Key Laboratory of Heavy Oil Processing China University of Petroleum

Nanomesh graphene （NMG） obtained by template chemical vapor deposition was used to synthesize the binder-free graphene monoliths by simple tablet pressing. The stacking manner of the NMG sheets was crucial to the cohesion interaction between the graphene sheets, only the NMG materials with a loosely stacking manner could be pressed into binder-free monoliths. At the tableting pressure of 2-8 MPa, both the bulk densities and the specific surface areas of the monoliths keep nearly constant as the tableting pressure increases, indicating that the NMG monoliths have obvious elasticity and a porous structure due to the large corrugations and the mesh structures of the graphene sheets. As a result, an extraordinary methane storage capacity of 236 （v/v） at 9 MPa was obtained in the graphene monolith prepared by tabletin~ at 4 MPa.

关键词： Binder-freeGrapheneMonolithsMethane storage

Retrieval of middle and upper atmospheric wind based on non-full circular fringe recorded by Fabry-Perot Inteferometer

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Science China Earth Sciences 2017年第9期60卷 1732-1738页

作者： WANG HouMao WANG Chong WANG YongMei zhang xiaoxin HUANG Cong LIANG ShaoLin National Space Science Center Chinese Academy of Sciences Beijing 100190 China Institute of Shanghai Satellite Engineering Shanghai 201109 China National Satellite Meteorological Center China Meteorological Administration Beijing 100081 China

Fabry-Perot Interferometer(FPI) has been used widely for wind measurements of the middle and upper *** date, most of FPIs have been based on full-closed circular fringe, which needs 15–25 min to obtain a group of wind velocity(zonal and meridional). However, it is hard to improve the temporal resolution because full-closed circular fringe in several directions cannot be easily imaged onto the same Charge-Coupled Device(CCD) with enough airglow intensity. In this paper, a data processing method is proposed for non-full circular fringe of FPI, which can support CCD with enough area of observations in several directions simultaneously. The method is focused on the center determination of non-full fringe. It includes radial cross-section, peak coordinate determination, and center calculation. Based on the calculated center, the fringe is annular summed. Then its radius is determined subsequently using Gaussian fitting. Finally, the wind is retrieved from the fringe radius. For validation, fringes from two ground-based FPIs were used, which are deployed in Kelan(38.71°N, 111.58°E) and Xinglong(40.40°N, 117.59°E) in China. The results retrieved from non-full fringes of FPIs were compared with that from full-closed circular fringe. The averaged wind deviation between them demonstrates reasonable difference with 5.38 ms^-(1) for 892.0 nm airglow emission, 5.81 ms^-(1) for 630.0 nm emission, and 3.03 ms^-(1) for 557.7 nm emission. Besides, wind results of Xinglong FPI are compared roughly with measurements of meteor radar which is deployed in Ming Tombs of Beijing(40.3°N,116.2°E). Good agreement demonstrates that this method is robust enough for FPI wind retrieval of mesosphere and thermosphere.

关键词： Fabry-Perot Interferometer(FPI) Wind retrieval Non-full circular fringe Full-closed circular fringe

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静磁场下电子束运动行为仿真

中国有色金属学报 2024年第7期34卷 2343-2355页

作者：田智睿付维达郝龙张小新蒋丹青胡涛陈超越余建波谭毅任忠鸣无省部共建高品质特殊钢冶金与制备国家重点实验室上海200444 上海市钢铁冶金新技术开发应用重点实验室上海200444 上海大学材料科学与工程学院上海200444 上海市集成电路与新型显示材料工程研究中心上海200444 大连理工大学材料科学与工程学院大连116024

电子束具有能量集中、能量转化效率高等特点,广泛用于金属精炼、增材制造等金属加工领域。在电子束熔炼过程中引入外磁场,可调控熔体流动与凝固组织,改善材料性能,但磁场会导致电子束偏转,造成熔区偏移。针对此问题,本研究基于COMSOL仿... 详细信息

电子束具有能量集中、能量转化效率高等特点,广泛用于金属精炼、增材制造等金属加工领域。在电子束熔炼过程中引入外磁场,可调控熔体流动与凝固组织,改善材料性能,但磁场会导致电子束偏转,造成熔区偏移。针对此问题,本研究基于COMSOL仿真软件对静磁场下电子与电子束在不同外加磁场强度、发射角、扫描角及发射距离参数下的运动行为进行建模与仿真分析。结果表明:磁场下电子束与单电子的运动行为相似;在一定外加磁场下实现电子束熔炼需满足一定的临界发射角和扫描角条件,如在背景磁场为0.15 T时,发射角需小于35°,且当发射角为0°时,扫描角介于−3.5°~+3.5°之间;磁场越强,电子(束)偏转越剧烈,其临界条件范围越窄;磁场对电子(束)具有筛选、聚焦及约束作用,在满足临界发射角和扫描角条件下任意发射距离的电子(束)均能进入坩埚。本研究可为磁场辅助电子束熔炼及其他相关技术的开发提供指导。

关键词：电子束熔炼磁场带电粒子运动数值模拟

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吴茱萸多糖的提取纯化与结构解析

南昌大学学报（理科版） 2024年第3期48卷 261-270页

作者：张晓新范春娟王君巧聂少平南昌大学食品科学与资源挖掘全国重点实验室江西南昌330047 南昌大学中国-加拿大食品科学与技术联合实验室江西南昌330047

以吴茱萸为原料,先对水提醇沉获得的吴茱萸粗多糖分离纯化再对纯化后的均一组分进行结构表征。首先,根据多糖保留率、脱色率和分子量变化等指标,确定最适合吴茱萸多糖(EFP)的脱色方法;其次,通过乙醇分级沉淀获得吴茱萸多糖纯化组分EFP-2... 详细信息

以吴茱萸为原料,先对水提醇沉获得的吴茱萸粗多糖分离纯化再对纯化后的均一组分进行结构表征。首先,根据多糖保留率、脱色率和分子量变化等指标,确定最适合吴茱萸多糖(EFP)的脱色方法;其次,通过乙醇分级沉淀获得吴茱萸多糖纯化组分EFP-20。采用比色法、高效凝胶渗透色谱仪(HPGPC)、离子色谱(HPAEC-PAD)、甲基化处理结合气相色谱-质谱(GC-MS)和核磁共振(NMR)分析其化学组成、分子量和糖苷键类型等结构特征。结果表明,活性炭对吴茱萸多糖的脱色效果最好,其脱色率达68.74%,且中性糖、糖醛酸保留率分别为94.26%和91.79%。通过乙醇分级沉淀获得的多糖组分EFP-20分子量为1.78×10^(7) Da,主要由鼠李糖(20.83%)、阿拉伯糖(23.16%)、半乳糖(31.52%)和半乳糖醛酸(23.64%)组成。甲基化结果表明主要的糖苷键为T-Arap(20.99%)、1,2,4-Rhap(21.82%)、1,4-Galp(11.05%)、1,2-GalpA(14.33%)和1,4-GalpA(11.05%),结合核磁共振分析推断EFP-20是一种果胶,含有I型鼠李半乳糖醛酸聚糖型结构域,该结构域主链由α-1,4-GalpA和α-1,2,4-Rhap重复残基组成,分支点在C-4位。通过对吴茱萸多糖提取方法和结构特征的研究可作为重要中药资源及为相关功能活性产品的开发利用提供基础数据和理论支持。

关键词：吴茱萸多糖分离结构

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创新管理视角下地方本科院校在地国际化发展路径探析

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邢台学院学报 2024年第2期39卷 188-192页

作者：董月娟任宇红张晓鑫河北师范大学河北石家庄050010 北京师范大学北京100875

在经济全球化和信息技术变革不断推进的背景下,高等教育国际化发展受到逆全球化变局、多国复杂政治形势、全球公共卫生安全事件等因素交织影响,在新发展格局下面临更多的不确定性和挑战。地方本科高校在国际化发展中,面临人员跨国流动... 详细信息

在经济全球化和信息技术变革不断推进的背景下,高等教育国际化发展受到逆全球化变局、多国复杂政治形势、全球公共卫生安全事件等因素交织影响,在新发展格局下面临更多的不确定性和挑战。地方本科高校在国际化发展中,面临人员跨国流动受阻、在线教学有效措施不足、完全本土国际化实现条件不充分等现实困难。从德鲁克创新管理思想中汲取经验,结合地方本科院校面临的教育国际化现状及困难,从构建合理有序的在地国际化组织结构、创新国际化人才引进和培育机制、服务于学生成长成才、与国家战略发展相衔接四方面,对优化在地国际化发展路径提出对策,推动地方本科院校国际化提质增效,提升地方本科院校的国际影响力和竞争力。

关键词：地方本科院校在地国际化创新管理

Comparison of a new model with previous models for the low-latitude magnetopause size and shape

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Chinese Science Bulletin 2010年第2期55卷 179-187页

作者： LIN RuiLin zhang xiaoxin LIU SiQing WANG YongLi GONG JianCun Centerfor Space Science and Applied Research Chinese Academy of Sciences Beijing 100190 China Graduate University of Chinese Academy of Sciences Beijing 100049 China National Center for Space Weather China Meteorological Administration Beijing 100081 China NASA/Goddard Space Flight Center Greenbelt Maryland 20771 USA

In this study, the advantages and the limitations of previous low-latitude magnetopause empirical models are discussed. In order to overcome their limitations and inherit their advantages, a new continuous function for the influence of the interplanetary magnetic field (IMF) Bz on the magnetopause, the Shue model function and the 613 low-latitude magnetopause crossings are used to construct a new low-latitude magnetopause model parameterized by the solar wind dynamic pressure (Dp) and IMF Bz. In comparison with the previous low-latitude magnetopause models, it is found that the new model improves the prediction capability and has a large range of validity for the low-latitude magnetopause. In addition, it is also demonstrated that the new model and the previous low-latitude magnetopause models are not appropriate for predicting the high-latitude magnetopause.

关键词：磁层顶低纬度国际货币基金组织型号形状行星际磁场经验模型连续函数

Channel Stability Analysis by One-Way Fluid Structure Interaction: A Case Study in China

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Transactions of Tianjin University 2017年第5期23卷 451-460页

作者： Xiaobin Zhu Xiaoling Wang Minghui Liu Zhen Wang xiaoxin zhang State Key Laboratory of Hydraulic Engineering Simulation and Safety Tianjin University Tianjin 300072 China

Channel engineering stability with underground goafs is a complex three-dimensional problem, especially when considering channel leakage, and is influenced by a number of processes, such as seepage, fluid structure interaction (FSI), modeling, and selection of geological mechanical parameters. In this study, stability finite element analysis by one-way FSI was performed by establishing an integrated 3D engineering geological model. The extended Fourier amplitude sensitivity test was used to quantitatively assess the first-order and total sensitivities of the engineering model to critical geological mechanical parameters. Results illustrate that the channel engineering deformation is under a reasonable range and the elastic modulus is the highest total sensitivity parameter for the channel tilt and curvature at 0.7395 and 0.7525, respectively. Moreover, the most observable coupling effects for the curvature and horizontal strain are cohesion (0.1933) and density (0.7410), respectively. © 2017, Tianjin University and Springer-Verlag GmbH Germany.

关键词： Elastic moduli Fluid structure interaction Geology Stability

The geometric factor of high energy protons detector on FY-3 satellite

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Science China Earth Sciences 2014年第11期57卷 2558-2566页

作者： zhang ShenYi zhang XianGuo WANG ChuiQin SHEN GuoHong JIN Tao zhang BinQuan SUN YueQiang ZHU GuangWu LIANG JinBao zhang xiaoxin LI JiaWei HUANG Cong HAN Ying Center for Space Science and Applied Research Chinese Academy of Sciences National Center for Space Weather Beijing Institute of Petrochemical Technology

Geometric factor is the key parameter for inversion of particle spectrum in space particle detection. Traditional geometric factor is obtained through the method of numerical calculation with the actual structure of the detector as the input condition. The degree of accuracy for data inversion is reduced since traditional geometric factor fails to take into account the physical process of interaction between the particle and substance as well as the influence of factors such as the particle interference between different energy channels on the measurement result. Here we propose an improved geometrical factor calculation method, the concept of which is to conduct actual structural modelling of the detector in the GEANT4 program, consider the process of interaction between the particle and substance, obtain the response function of the detector to particles of different energy channels through the method of Monte Carlo simulation, calculate the influence of contaminated particle on the geometrical factor, and finally get the geometrical factors for different energy channels of the detector. The imrpoved geometrical factor obtained through the method has carried out inversion for the data of high energy protons detector on China's FY-3 satellite, the energy spectrum after which is more in line with the power law distribution recognized by space physics. The comparison with the measured result of POES satellite indicates that the FY-3 satellite data are in good accordance with the satellite data, which shows the method may effectively improve the quality of data inversion.

关键词： geometrical factor response function particle radiation space detection FY-3

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